A Nasaastronaut has shared the adorable moment she reunited with her dog after returning from a 328-day journey to space.

On Thursday, Christina Koch tweeted a video of the moment she walked through the door to greet her puppy, Sadie Lou, with the caption: “Not sure who was more excited. Glad she remembers me after a year!”

In the video, Sadie Lou is seen pawing at the door as she sees her owner approaching, before rushing out the door to greet her.

While wagging her tail ecstatically, the dog then jumps on Koch and proceeds to lick her face, as the astronaut says: “Hi baby girl!”

The heartwarming clip of the pair’s reunion has since been viewed more than 3.4m times and liked more than 126,000 times on Twitter.

Another said: “Welcome back to Earth! Clearly your puppy loves and missed you and is so happy you’re home. Nothing better than the unconditional love of your pets. And congratulations for setting a new record for time spent in space.”

On Wednesday, Koch discussed the happy reunion with reporters at Houston’s Johnson Space Centre, where she revealed that Sadie Lou, a rescue, also goes by the nickname “LBD” or “little brown dog”.

“She’s from the Humane Society and she couldn’t be sweeter,” she said. “And yes, she was very excited, I was very excited, I”m not sure who was more excited!

“You know it’s just a symbol of coming back to the people and places that you love, to see your favourite animal."

Koch’s homecoming comes after she made history with her recent trip to outer space.

During her journey - which broke the record for the longest space mission by a woman - Koch also participated in the first all-female spacewalk, alongside astronaut Jessica Meir.

The previous record for longest single space flight, held by Nasa astronaut Peggy Whitson, was 288 days.

After breaking the record, Koch told reporters in December: “Having the opportunity to be up here for so long is truly an honour.

“Peggy is a heroine of mine and has also been kind enough to mentor me through the years, so it is a reminder to give back and to mentor when I get back.

“It is a wonderful thing for science. We see another aspect of how the human body is affected by microgravity for the long term. That is really important for our future space flight plans, going forward to the moon and Mars.”